MEMS-Enabled On-Chip Computational Mid-Infrared Spectrometer Using Silicon Photonics

On-chip spectrometers using silicon photonics offer a compact, energy-efficient, and cost-effective solution to biochemical spectroscopy and hyperspectral imaging in integrated and portable application scenarios. The mid-infrared (MIR) spectral band is critical to spectroscopic sensing. However, the existing on-chip spectrometer approaches are limited in the MIR. Here, we present an on-chip computational spectrometer in MIR (3.7–4.05 μm) using an MEMS-enabled silicon photonic integrated device, which is realized via the time-domain modulation of reconfigurable waveguide couplers. The electrostatically actuated on-chip spectrometer intrinsically features low power consumption and single-pixel detection and offers multiplexing advantages, potentially leading to a high signal-to-noise ratio. We achieve laser spectrum reconstruction across a large bandwidth (350 nm) experimentally. Furthermore, based on a linear superposition assumption, we achieve the polychromatic light reconstruction of narrow spectral features (3 nm resolution) and a broad absorption spectrum of nitrous oxide gas using a regularized regression method.